Flow control valve and temperature control device using same

ABSTRACT

Provided is a flow rate control valve capable of suppressing leakage of a fluid when the flow rate control valve completely closes a valve port as compared to a flow rate control valve that does not include a gap reducing portion being provided so as to partially reduce a gap between a valve body and a member opposed to the valve body, and a temperature control device using the flow rate control valve. The flow rate control valve includes: a valve main body including a valve seat, the valve seat having a columnar space and having one or a plurality of valve ports, which allow a fluid to flow therethrough and each have a rectangular cross section; a valve body being provided in a freely rotatable manner in the valve seat of the valve main body so as to open and close the one or the plurality of valve ports, the valve body having a cylindrical shape and having an opening formed in an outer peripheral surface of the valve body; a gap reducing portion being provided so as to partially reduce a gap between the valve body and a member opposed to the valve body; and drive means for driving the valve body to rotate.

TECHNICAL FIELD

The present invention relates to a flow rate control valve and atemperature control device using the same.

BACKGROUND ART

Hitherto, as a technology relating to a flow rate control valve, theapplicant of the present invention has already proposed a three-wayvalve for flow rate control disclosed in, for example, Patent Literature1.

The three-way valve for flow rate control disclosed in Patent Literature1 includes: a valve main body including a valve seat, the valve seathaving a columnar space and having a first valve port, which allowsinflow of a first fluid and has a rectangular cross section, and asecond valve port, which allows inflow of a second fluid and has arectangular cross section; a valve body being provided in a freelyrotatable manner in the valve seat of the valve main body so as tosimultaneously switch the first valve port from a closed state to anopened state and switch the second valve port from an opened state to aclosed state, the valve body having a half-cylindrical shape with apredetermined central angle and having a curved-surface shape at each ofboth end surfaces of the valve body in a circumferential direction; anddrive means for driving the valve body to rotate.

CITATION LIST Patent Literature

[PTL 1] JP 6104443 B1

SUMMARY OF INVENTION Technical Problem

The present invention provides a flow rate control valve capable ofsuppressing leakage of a fluid when the flow rate control valvecompletely closes a valve port as compared to a flow rate control valvethat does not include a gap reducing portion being provided so as topartially reduce a gap between a valve body and a member opposed to thevalve body, and provides a temperature control device using the flowrate control valve.

Solution to Problem

According to the invention of item 1, provided is a flow rate controlvalve, including:

a valve main body including a valve seat, the valve seat having acolumnar space and having one or a plurality of valve ports, which allowa fluid to flow therethrough and each have a rectangular cross section;

a valve body being provided in a freely rotatable manner in the valveseat of the valve main body so as to open and close the one or theplurality of valve ports, the valve body having a cylindrical shape andhaving an opening formed in an outer peripheral surface of the valvebody;

a gap reducing portion being provided so as to partially reduce a gapbetween the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of item 2, provided is a flow rate controlvalve, including:

a valve main body including a valve seat, the valve seat having acolumnar space and having a first valve port, which allows inflow of afirst fluid and has a rectangular cross section, and a second valveport, which allows inflow of a second fluid and has a rectangular crosssection;

a valve body being provided in a freely rotatable manner in the valveseat of the valve main body so as to simultaneously switch the firstvalve port from a closed state to an opened state and switch the secondvalve port from an opened state to a closed state, the valve body havinga half-cylindrical shape with a predetermined central angle and having acurved-surface shape or a flat-surface shape at each of both endsurfaces of the valve body in a circumferential direction;

a gap reducing portion being provided so as to partially reduce a gapbetween the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of item 3, provided is a flow rate controlvalve, including:

a valve main body including a valve seat, the valve seat having acolumnar space and having a first valve port, which allows outflow of afluid and has a rectangular cross section, and a second valve port,which allows outflow of the fluid and has a rectangular cross section;

a valve body being provided in a freely rotatable manner in the valveseat of the valve main body so as to simultaneously switch the firstvalve port from a closed state to an opened state and switch the secondvalve port from an opened state to a closed state, the valve body havinga half-cylindrical shape with a predetermined central angle and having acurved-surface shape or a flat-surface shape at each of both endsurfaces of the valve body in a circumferential direction;

a gap reducing portion being provided so as to partially reduce a gapbetween the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of item 4, provided is a flow rate controlvalve, including:

a valve main body including a valve seat having a columnar space, thevalve main body having a first valve port, which allows a fluid to flowtherethrough and has a rectangular cross section, and a third valveport, which allows the fluid to flow therethrough, the first valve portbeing formed in a peripheral surface of the valve seat, the third valveport being formed in one end portion of the valve seat in an axialdirection;

a valve body being provided in a freely rotatable manner in the valveseat of the valve main body, the valve body having a shape correspondingto part of a cylindrical shape with a predetermined central angle, so asto linearly change an opening area of the first valve port;

a gap reducing portion being provided so as to partially reduce a gapbetween the valve body and a member opposed to the valve body; and

drive means for driving the valve body to rotate.

According to the invention of item 5, in the flow rate control valve asdescribed in item 1, the one or the plurality of valve ports are eachformed by a valve port forming member, which is a member providedseparately from the valve main body, and

in which the gap reducing portion is formed of a distal end portion ofthe valve port forming member opposed to the valve body.

According to the invention of item 6, the flow rate control valve asdescribed in item 5 further includes a gap adjusting member configuredto adjust a gap between the valve body and the gap reducing portion.

According to the invention of item 7, provided is a temperature controldevice, including:

temperature control means having a flow passage for temperature control,which allows a fluid for temperature control to flow therethrough, thefluid for temperature control including a lower temperature fluid and ahigher temperature fluid adjusted in mixture ratio;

first supply means for supplying the lower temperature fluid adjusted toa first predetermined lower temperature;

second supply means for supplying the higher temperature fluid adjustedto a second predetermined higher temperature; and

a flow rate control valve connected to the first supply means and thesecond supply means, and configured to adjust the mixture ratio betweenthe lower temperature fluid supplied from the first supply means and thehigher temperature fluid supplied from the second supply means and allowthe fluid for temperature control to flow through the flow passage fortemperature control,

in which the flow rate control valve of any one of items 1, 2, 5, and 6is used as the flow rate control valve.

According to the invention of item 8, provided is a temperature controldevice, including:

temperature control means having a flow passage for temperature control,which allows a fluid for temperature control to flow therethrough, thefluid for temperature control including a lower temperature fluid and ahigher temperature fluid adjusted in mixture ratio;

first supply means for supplying the lower temperature fluid adjusted toa first predetermined lower temperature;

second supply means for supplying the higher temperature fluid adjustedto a second predetermined higher temperature;

mixing means, which is connected to the first supply means and thesecond supply means, for mixing the lower temperature fluid suppliedfrom the first supply means and the higher temperature fluid suppliedfrom the second supply means and supplying a mixture of the lowertemperature fluid and the higher temperature fluid to the flow passagefor temperature control; and

a flow rate control valve configured to divide the fluid for temperaturecontrol having flowed through the flow passage for temperature controlbetween the first supply means and the second supply means whilecontrolling a flow rate of the fluid for temperature control,

in which the flow rate control valve of any one of items 1, 3, 5, and 6is used as the flow rate control valve.

Advantageous Effects of Invention

According to the present invention, a flow rate control valve capable ofsuppressing leakage of a fluid when the flow rate control valvecompletely closes a valve port as compared to a flow rate control valvethat does not include a gap reducing portion being provided so as topartially reduce a gap between a valve body and a member opposed to thevalve body, and a temperature control device using the flow rate controlvalve can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view for illustrating an outer appearance of athree-way motor valve as one example of a three-way valve for flow ratecontrol according to a first embodiment of the present invention.

FIG. 2 are views including a front view, a right side view thereof, anda bottom view of an actuator, for illustrating the three-way motor valveas one example of the three-way valve for flow rate control according tothe first embodiment of the present invention.

FIG. 3 is a sectional view taken along the line A-A of FIG. 2(b), forillustrating the three-way motor valve as one example of the three-wayvalve for flow rate control according to the first embodiment of thepresent invention.

FIG. 4 is a sectional perspective view for illustrating relevant partsof the three-way motor valve as one example of the three-way valve forflow rate control according to the first embodiment of the presentinvention.

FIG. 5 is an exploded perspective view, which is partially in sectionalview, for illustrating the relevant parts of the three-way motor valveas one example of the three-way valve for flow rate control according tothe first embodiment of the present invention.

FIG. 6 are configuration views for illustrating a valve seat.

FIG. 7 is a horizontal sectional configuration view for illustrating afitted state of the valve seat.

FIG. 8 is a perspective configuration view for illustrating an adjustingring.

FIG. 9 are schematic sectional views for illustrating an opened stateand a closed state of a valve shaft.

FIG. 10 are configuration views for illustrating the valve shaft.

FIG. 11 are schematic sectional views for illustrating another valveshafts.

FIG. 12 are schematic sectional views for illustrating still anothervalve shaft.

FIG. 13 is a graph for showing characteristics of the three-way motorvalve as one example of the three-way valve for flow rate controlaccording to the first embodiment of the present invention.

FIG. 14 is a graph for showing characteristics of the three-way motorvalve as one example of the three-way valve for flow rate controlaccording to the first embodiment of the present invention.

FIG. 15 is a table for showing results of Experiment Example 2.

FIG. 16 is a sectional configuration view for illustrating relevantparts of a three-way motor valve as one example of a three-way valve forflow rate control according to a second embodiment of the presentinvention.

FIG. 17 is a sectional configuration view for illustrating relevantparts of a three-way motor valve as one example of a three-way valve forflow rate control according to a third embodiment of the presentinvention.

FIG. 18 is a schematic diagram for illustrating a constant-temperaturemaintaining device (chiller device) to which the three-way motor valveas one example of the three-way valve for flow rate control according tothe first embodiment of the present invention is applied.

FIG. 19 is a schematic diagram for illustrating a constant-temperaturemaintaining device (chiller device) to which the three-way motor valveas one example of the three-way valve for flow rate control according tothe second embodiment of the present invention is applied.

DESCRIPTION OF EMBODIMENTS

In the following, embodiments of the present invention are describedwith reference to the drawings.

First Embodiment

FIG. 1 is a perspective view for illustrating an outer appearance of athree-way motor valve as one example of a flow rate control valveaccording to a first embodiment of the present invention. FIG. 2(a) is afront view. FIG. 2(b) is a right side view of FIG. 2(a). FIG. 2(c) is abottom view of an actuator. FIG. 3 is a sectional view taken along theline A-A of FIG. 2(b). FIG. 4 is a sectional perspective view forillustrating relevant parts of the three-way motor valve. FIG. 5 is anexploded perspective view for illustrating the relevant parts of thethree-way motor valve.

A three-way motor valve 1 is constructed as a rotary three-way valve. Asillustrated in FIG. 1, the three-way motor valve 1 mainly includes avalve portion 2 arranged at a lower portion thereof, an actuator 3arranged at an upper portion thereof, and a sealing portion 4 and acoupling portion 5, which are arranged between the valve portion 2 andthe actuator 3.

As illustrated in FIG. 2 to FIG. 5, the valve portion 2 includes a valvemain body 6 obtained by forming metal, for example, SUS, into asubstantially rectangular parallelepiped shape. As illustrated in FIG.3, a first inflow port 7 and a first valve port 9 are formed in one sidesurface (left side surface in the illustrated example) of the valve mainbody 6. The first inflow port 7 allows inflow of a lower temperaturefluid as a first fluid. The first valve port 9 has a rectangular crosssection, and communicates with a valve seat 8 having a columnar space.

In the first embodiment of the present invention, instead of directlyforming the first inflow port 7 and the first valve port 9 in the valvemain body 6, the first inflow port 7 and the first valve port 9 areformed in a first valve seat 70 as one example of a valve port formingmember, and the first valve seat 70 is fitted to the valve main body 6,thereby providing the first inflow port 7 and the first valve port 9.

As illustrated in FIG. 6, the first valve seat 70 integrally includes arectangular tube portion 71, a cylindrical portion 72, and a taperedportion 73. The rectangular tube portion 71 has a rectangular tube shapeand is provided inside the valve main body 6. The cylindrical portion 72has a cylindrical shape and is provided outside the valve main body 6.The tapered portion 73 has an outer diameter increasing toward thecylindrical portion 82 side and is arranged between the rectangular tubeportion 71 and the cylindrical portion 72. The first valve port 9 isformed in the rectangular tube portion 71 of the first valve seat 70,and has a rectangular prism shape having a rectangular cross section(square cross section in the first embodiment of the present invention).Further, the first inflow port 7 is formed in the cylindrical portion 72of the first valve seat 70, and has a columnar shape having a circularcross section substantially circumscribing the first valve port 9.

As a material for the first valve seat 70, for example, so-called “superengineering plastic” is used. The super engineering plastic has higherheat resistance and higher mechanical strength under a high temperaturethan ordinary engineering plastic. Examples of the super engineeringplastic include, for example, polyether ether ketone (PEET),polyphenylene sulfide (PPS), polyether sulfone (PES), polyamide imide(PAI), a liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE),polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), orcomposite materials thereof. As the material for the first valve sheet70, there may be used, for example, “TECAPEEK” (trademark) manufacturedby Ensinger Japan Co., Ltd. serving as a PEEK resin material for cuttingwork, and “TECAPEEK TF 10 blue” (product name) having blending therein10% PTFE, which is excellent in sliding property, is particularlysuitably used.

As illustrated in FIG. 4 and FIG. 5, a recess 76 is formed in the valvemain body 6 by, for example, machining. The recess 76 has a shapecorresponding to an outer shape of the first valve seat 70 and similarto the shape of the valve seat 70. The recess 76 includes a rectangulartube portion 76 a corresponding to the rectangular tube portion 71 ofthe first valve seat 70, a cylindrical portion 76 b corresponding to thecylindrical portion 72, and a tapered portion 76 c corresponding to thetapered portion 73. The first valve seat 70 is fitted in the recess 76of the valve main body 6 in a liquid-tight manner. Further, asillustrated in FIG. 3 and FIG. 4, a slight gap is defined between thetapered portion 73 of the first valve seat 70 and the tapered portion 76c of the recess 76. As a result, under a state in which the first valveseat 70 is fitted in the recess 76 of the valve main body 6, by adistance corresponding to the slight gap between the tapered portion 73and the tapered portion 76 c of the recess 76, the valve seat 70 isfreely movable by a length of from about several hundred micrometers toabout several millimeters along inward and outward directions of thevalve main body 6, and the fitting position of the valve seat 70 isadjustable.

As illustrated in FIG. 6(b), a concave portion 74 is formed at a distalend of the rectangular tube portion 71 of the first valve seat 70. Theconcave portion 74 is one example of a gap reducing portion having anarc shape in plan view, which forms part of a curved surface of acolumnar shape corresponding to the valve seat 8 having a columnar shapein the valve main body 6. A curvature radius R of the concave portion 74is set to a value substantially equal to a curvature radius of the valveseat 8 or a curvature radius of a valve shaft 34. In order to preventbiting of the valve shaft 34 to be rotated inside the valve seat 8, asdescribed later, the valve seat 8 of the valve main body 6 defines aslight gap with respect to an outer peripheral surface of the valveshaft 34. As illustrated in FIG. 7, the concave portion 74 of the firstvalve seat 70 is fitted so as to protrude toward the valve shaft 34 sidemore than the valve seat 8 of the valve main body 6 under a state inwhich the first valve seat 70 is fitted to the valve main body 6. As aresult, a gap G between the valve shaft 34 and an inner surface of thevalve seat 8 of the valve main body 6 being a member opposed to thevalve shaft 34 is partially set to a value reduced by the protrudingamount of the concave portion 74 of the first valve seat 70 as comparedto that of a gap between the valve shaft 34 and another portion of thevalve seat 8. Thus, a gap G1 between the concave portion 74 of the firstvalve seat 70 and the valve shaft 34 is set to a desired value (G1<G2)smaller than (or a gap narrower than) a gap G2 between the valve shaft34 and the inner surface of the valve seat 8. The gap G1 between theconcave portion 74 of the first valve seat 70 and the valve shaft 34 maycorrespond to a state in which the concave portion 74 of the valve seat70 is held in contact with the valve shaft 34, that is, a state in whichno gap is defined (the gap G1=0).

However, in a case in which the concave portion 74 of the first valveseat 70 is held in contact with the valve shaft 34, there is a fear inthat rotational torque of the valve shaft 34 is increased due to contactresistance of the concave portion 74 when the valve shaft 34 is drivento rotate. Accordingly, a contact degree of the concave portion 74 ofthe first valve seat 70 with the valve shaft 34 is adjusted inconsideration of the rotational torque of the valve shaft 34. That is,the contact degree is adjusted to such an extent as to involve noincrease in the rotational torque of the valve shaft 34 or involveslight increase even when the rotational torque is increased, and causeno trouble for rotation of the valve shaft 34.

As illustrated in FIG. 6, an annular portion 75 is formed on an outerend surface of the cylindrical portion 72 of the first valve seat 70.The annular portion 75 has an outer diameter smaller than that of thecylindrical portion 72, and has a cylindrical shape having a smallthickness and a short length. An O-ring 15 is externally fitted to theannular portion 75 of the first valve seat 70. The O-ring 15 is made ofa synthetic resin having heat resistance, and has an annular shapehaving a circular or rectangular cross section. An O-ring retainer 16 isfitted to an outer side of the O-ring 15. The O-ring retainer 16 is madeof a synthetic resin having heat resistance or metal, and has an annularshape having a rectangular cross section. Moreover, an adjusting ring 77is arranged on an outer side of the first valve seat 70. The adjustingring 77 is one example of a gap adjusting member configured to adjustthe gap G1 between the valve shaft 34 and the concave portion 74 of thefirst valve seat 70. As illustrated in FIG. 8, the adjusting ring 77 ismade of a synthetic resin having heat resistance or metal, and is formedof a cylindrical member having a relatively small length and a malethread 77 a formed in an outer peripheral surface thereof. Recessedgrooves 77 b are formed in an outer end surface of the adjusting ring 77so as to be 180 degrees opposed to each other. When the adjusting ring77 is fastened and fitted into a female thread portion 78 formed in thevalve main body 6, a jig (not shown) for adjusting a fastening amount islocked to the recessed grooves 77 b so as to turn the adjusting ring 77.

The female thread portion 78 for fitting the adjusting ring 77 is formedin the valve main body 6. A tapered portion 79 is formed at an openingend portion located on an outer side of the female thread portion 78,and has a diameter increasing toward an outer periphery thereof. AnO-ring 79 a is interposed in the tapered portion 79.

The adjusting ring 77 is configured to adjust an amount (distance) ofpushing and moving the first valve seat 70 inward by the adjusting ring77 through adjustment of a fastening amount of the adjusting ring 77with respect to the female thread portion 78 of the valve main body 6.When the fastening amount of the adjusting ring 77 is increased, asillustrated in FIG. 7, the first valve seat 70 is pushed by theadjusting ring 77 through intermediation of the O-ring retainer 16 sothat the concave portion 74 protrudes from an inner peripheral surfaceof the valve seat 8 and is displaced in a direction of approaching thevalve shaft 34. Thus, the gap G1 between the concave portion 74 and thevalve shaft 34 is reduced. Further, when the fastening amount of theadjusting ring 77 is set to a small amount in advance, the distance ofpushing and moving the first valve seat 70 by the adjusting ring 77 isreduced. As a result, the first valve seat 70 is arranged apart from thevalve shaft 34, and the gap G1 between the concave portion 74 of thefirst valve seat 70 and the valve shaft 34 is relatively increased. Themale thread 77 a of the adjusting ring 77 and the female thread portion78 of the valve main body 6 are each set to have a small pitch. Withthis configuration, a protruding amount of the first valve seat 70 canbe finely adjusted.

Further, as illustrated in FIG. 3 and FIG. 4, a first flange member 10,which is configured to connect a pipe (not shown) allowing inflow of thelower temperature fluid, is mounted to one side surface of the valvemain body 6 with four hexagon socket head cap screws 11 (see FIG. 3). InFIG. 5, a reference symbol 11 a denotes a screw hole in which thehexagon socket head cap screw 11 is fastened. Similarly to the valvemain body 6, the first flange member 10 is made of metal, for example,SUS. The first flange member 10 includes a flange portion 12, aninsertion portion 13, and a pipe connecting portion 14. The flangeportion 12 has a side surface having the same rectangular shape as theside surface of the valve main body 6. The insertion portion 13 has acylindrical shape and protrudes from an inner surface of the flangeportion 12 (see FIG. 4). The pipe connecting portion 14 has asubstantially cylindrical shape having a large thickness and protrudesfrom an outer surface of the flange portion 12. A pipe (not shown) isconnected to the pipe connecting portion 14. An inner periphery of thepipe connecting portion 14 is set to, for example, Rc ½ being a standardfor a tapered female thread having a bore diameter of about 21 mm, or afemale thread having a diameter of about 0.58 inches. The shape of thepipe connecting portion 14 is not limited to the tapered female threador the female thread. The pipe connecting portion 14 may have, forexample, a tube fitting shape that allows a tube to be fitted thereto.The pipe connecting portion 14 may have any shape as long as the pipeconnecting portion 14 enables inflow of a fluid through the first inflowport 7.

A second inflow port 17 and a second valve port 18 are formed in anotherside surface (right side surface in FIG. 3) of the valve main body 6.The second inflow port 17 allows inflow of a higher temperature fluid asa second fluid. The second valve port 18 has a rectangular crosssection, and communicates with the valve seat 8 having the columnarspace.

In the first embodiment of the present invention, instead of directlyforming the second inflow port 17 and the second valve port 18 in thevalve main body 6, the second inflow port 17 and the second valve port18 are formed in a second valve seat 80 as one example of the valve portforming member, and the second valve seat 80 is fitted to the valve mainbody 6, thereby providing the second inflow port 17 and the second valveport 18.

The second valve seat 80 has a configuration similar to theconfiguration of the first valve seat 70 as illustrated in FIG. 6 withthe reference symbol of the second valve seat 80 put in parentheses.That is, the second valve seat 80 integrally includes a rectangular tubeportion 81, a cylindrical portion 82, and a tapered portion 83. Therectangular tube portion 81 has a rectangular tube shape and is providedinside the valve main body 6. The cylindrical portion 82 has acylindrical shape and is provided outside the valve main body 6. Thetapered portion 83 has an outer diameter increasing toward thecylindrical portion 82 side and is arranged between the rectangular tubeportion 81 and the cylindrical portion 82. The second valve port 18 isformed in the rectangular tube portion 81 of the second valve seat 80,and has a rectangular prism shape having a rectangular cross section(square cross section in the first embodiment of the present invention).Further, the second inflow port 17 is formed in the cylindrical portion82 of the second valve seat 80, and has a cylindrical shape having acircular cross section substantially circumscribing the second valveport 18.

As illustrated in FIG. 4 and FIG. 5, a recess 86 is formed in the valvemain body 6 by, for example, machining. The recess 86 has a shapecorresponding to an outer shape of the second valve seat 80 and similarto the shape of the valve seat 80. The recess 86 includes a rectangulartube portion 86 a corresponding to the rectangular tube portion 81 ofthe second valve seat 80, a cylindrical portion 86 b corresponding tothe cylindrical portion 82, and a tapered portion 86 c corresponding tothe tapered portion 83. The second valve seat 80 is fitted in the recess86 of the valve main body 6 in a liquid-tight manner. Further, asillustrated in FIG. 3 and FIG. 4, a slight gap is defined between thetapered portion 83 of the second valve seat 80 and the tapered portion86 c of the recess 86. As a result, under a state in which the secondvalve seat 80 is fitted in the recess 86 of the valve main body 6, by adistance corresponding to the slight gap between the tapered portion 83and the tapered portion 86 c of the recess 86, the valve seat 80 isfreely movable by a length of from about several hundred micrometers toabout several millimeters along inward and outward directions of thevalve main body 6, and the fitting position of the valve seat 80 isadjustable. The second valve seat 80 is made of the same material asthat for the first valve seat 70.

As illustrated in FIG. 6, an annular portion 85 is formed on an outerend surface of the cylindrical portion 82 of the second valve seat 80.The annular portion 85 has an outer diameter smaller than that of thecylindrical portion 82, and has a cylindrical shape having a shortlength and a small thickness. An O-ring 24 is externally fitted to theannular portion 85 of the second valve seat 80. Further, an O-ringretainer 25 is fitted to an outer side of the O-ring 24. Moreover, anadjusting ring 87 is arranged on an outer side of the second valve seat80. The adjusting ring 87 is one example of a gap adjusting memberconfigured to adjust a gap G3 between the valve shaft 34 and a distalend portion 84 of the second valve seat 80. The value of the gap G3 isset to be the same as the gap G1. As illustrated in FIG. 8 with thereference symbol of the adjusting ring 87 put in parentheses, theadjusting ring 87 is formed of a cylindrical member having a relativelysmall length and a male thread 87 a formed in an outer peripheralsurface thereof. Recessed grooves 87 b are formed in an outer endsurface of the adjusting ring 87 so as to be 180 degrees opposed to eachother. When the adjusting ring 87 is fastened and fitted into a femalethread portion 88 formed in the valve main body 6, a jig (not shown) foradjusting a fastening amount is locked to the recessed grooves 87 b soas to turn the adjusting ring 87.

The female thread portion 88 for fitting the adjusting ring 87 is formedin the valve main body 6. A tapered portion 89 is formed at an openingend portion located on an outer side of the female thread portion 88,and has a diameter increasing toward an outer periphery thereof. AnO-ring 89 a is interposed in the tapered portion 89.

As illustrated in FIG. 3 and FIG. 4, a second flange member 19 forconnecting a pipe (not shown) which allows inflow of the highertemperature fluid is mounted to the another side surface of the valvemain body 6 with four hexagon socket head cap screws 20 (see FIG. 3).Similarly to the first flange member 10, the second flange member 19 ismade of metal, for example, SUS. The second flange member 19 has aflange portion 21, an insertion portion 22, and a pipe connectingportion 23. The flange portion 21 has a side surface having the samerectangular shape as the side surface of the valve main body 6. Theinsertion portion 22 has a cylindrical shape and protrudes from an innersurface of the flange portion 21. The pipe connecting portion 23 has asubstantially cylindrical shape having a large thickness and protrudesfrom an outer surface of the flange portion 21. A pipe (not shown) isconnected to the pipe connecting portion 23. An inner periphery of thepipe connecting portion 23 is set to, for example, Rc ½ being a standardfor a tapered female thread having a bore diameter of about 21 mm, or afemale thread having a diameter of about 0.58 inches. Similarly to thepipe connecting portion 14, the shape of the pipe connecting portion 23is not limited to the tapered female thread or the female thread. Thepipe connecting portion 23 may have, for example, a tube fitting shapethat allows a tube to be fitted thereto. The pipe connecting portion 23may have any shape as long as the pipe connecting portion 23 enablesinflow of a fluid through the second inflow port 17.

Here, the lower temperature fluid as the first fluid and the highertemperature fluid as the second fluid are fluids to be used fortemperature control. A fluid having a relatively lower temperature isreferred to as “lower temperature fluid,” and a fluid having arelatively higher temperature is referred to as “higher temperaturefluid.” Thus, the lower temperature fluid and the higher temperaturefluid have a relative relationship. The lower temperature fluid is not afluid having an absolutely low temperature, and the higher temperaturefluid is not a fluid having an absolutely high temperature. As the lowertemperature fluid and the higher temperature fluid, for example, underair pressure of from 0 MPa to 1 MPa and within a temperature range offrom about 0° C. to about 80° C., water (such as pure water) adjusted toa temperature of from about 0° C. to about 30° C. and water (pure water)adjusted to a temperature of from about 50° C. to about 80° C. aresuitably used, respectively. Further, as the lower temperature fluid andthe higher temperature fluid, for example, within a temperature range offrom about −20° C. to about +120° C., there is used a fluid such afluorine-based inert liquid, for example, Fluorinert (trademark) andethylene glycol, which are neither frozen at a temperature of about −20°C. nor boiled at a temperature of about +120° C.

Further, as illustrated in FIG. 3, in a lower end surface of the valvemain body 6, an outflow port 26 having a circular cross section as thethird valve port is opened. The outflow port 26 allows outflow of afluid for temperature control, which is a mixture of the lowertemperature fluid and the higher temperature fluid. A third flangemember 27 for connecting a pipe (not shown) which allows outflow of thefluid for temperature control is mounted to the lower end surface of thevalve main body 6 with four hexagon socket head cap screws 28. Acylindrical portion 26 b is opened in a lower end portion of the outflowport 26 through a tapered portion 26 a. The tapered portion 26 a istapered and increased in diameter so as to allow the third flange member27 to be fitted thereto. Similarly to the first and second flangemembers 10 and 19, the third flange member 27 is made of metal, forexample, SUS. The third flange member 27 has a flange portion 29, aninsertion portion 30, and a pipe connecting portion 31. The flangeportion 29 has a planar surface having a rectangular shape, which issmaller than the lower end surface of the valve main body 6. Theinsertion portion 30 has a cylindrical shape and protrudes from an upperend surface of the flange portion 29. The pipe connecting portion 31 hasa substantially cylindrical shape having a large thickness and protrudesfrom a lower end surface of the flange portion 29. A pipe (not shown) isconnected to the pipe connecting portion 31. An inner periphery of thepipe connecting portion 31 is set to, for example, Rc ½ being a standardfor a tapered female thread having a bore diameter of about 21 mm and afemale thread having a diameter of about 0.58 inches. An innerperipheral end on a lower end of the third inflow port 26 of the valvemain body 6 has a chamfer 33 to allow an O-ring 32 to be mounted betweenthe third outflow port 26 of the valve main body 6 and the flangeportion 29 of the third flange member 27. The shape of the pipeconnecting portion 31 is not limited to the tapered female thread or thefemale thread. The pipe connecting portion 31 may have, for example, atube fitting shape that allows a tube to be fitted thereto. The pipeconnecting portion 31 may have any shape as long as the pipe connectingportion 31 enables outflow of a fluid through the outflow port 26.

The valve seat 8 is formed in a center of the valve main body 6. Thevalve seat 8 forms the first valve port 9 having a rectangular crosssection and the second valve port 18 having a rectangular cross sectionwhen the first valve seat 70 and the second valve seat 80 are fitted tothe valve main body 6. The valve seat 8 has a space having a columnarshape corresponding to an outer shape of a valve body to be describedlater. Further, part of the valve seat 8 is formed by the first valveseat 70 and the second valve seat 80. The valve seat 8 having a columnarshape is provided in a state of penetrating an upper end surface of thevalve main body 6. As illustrated in FIG. 9, the first valve port 9 andthe second valve port 18 provided to the valve main body 6 are arrangedin an axial symmetrical manner with respect to a center axis (rotationaxis) C of the valve seat 8 having a columnar shape. More specifically,the first valve port 9 and the second valve port 18 are arranged so asto be orthogonal to the valve seat 8 having a columnar shape. One endedge of the first valve port 9 is opened in a position opposed toanother end edge of the second valve port 18 through the center axis C,that is, in a position different by 180°. Further, another end edge ofthe first valve port 9 is opened in a position opposed to one end edgeof the second valve port 18 through the center axis C, that is, in aposition different by 180°. In FIG. 9, for convenience, illustration ofa gap between the valve seat 8 and the valve shaft 34 is omitted.

Further, as illustrated in FIG. 3 and FIG. 4, the first valve port 9 andthe second valve port 18 are openings each having a rectangular crosssection such as a square cross section and are formed through fittingthrough fitting of the first valve seat 70 and the second valve seat 80to the valve main body 6 as described above. A length of one side of thefirst valve port 9 and the second valve port 18 is set to be smallerthan a diameter of the first inflow port 7 and the second inflow port17. The first valve port 9 and the second valve port 18 have a crosssection having a rectangular shape inscribed in the first inflow port 7and the second inflow port 17.

As illustrated in FIG. 10, a valve shaft 34 as one example of the valvebody has an outer shape obtained by forming metal, for example, SUS,into a substantially columnar shape. The valve shaft 34 mainly includesa valve body portion 35, upper and lower shaft support parts 36 and 37,a sealing portion 38, and a coupling par 40, which are integrallyprovided. The valve body portion 35 functions as a valve body. The upperand lower shaft support parts 36 and 37 are provided above and below thevalve body portion 35, respectively, and support the valve shaft 34 in afreely rotatable manner. The sealing portion 38 is provided to an upperportion of the upper shaft support portion 36. The coupling portion 40is provided to an upper portion of the sealing portion 38 throughintermediation of a tapered portion 39.

The upper and lower shaft support parts 36 and 37 each have acylindrical shape having an outer diameter smaller than that of thevalve body portion 35 and having an equal diameter. A length of thelower shaft support portion 37 in an axial direction is set to beslightly larger than that of the upper shaft support portion 36. Asillustrated in FIG. 3, the lower shaft support portion 37 is supportedin a freely rotatable manner through intermediation of a bearing 41 by alower end of the valve seat 8 provided to the valve main body 6. Anannular support portion 42 supporting the bearing 41 is provided at alower portion of the valve seat 8 so as to protrude toward an innerperiphery. The bearing 41, the support portion 42, and the insertionportion 30 of the third flange member 27 are set to have an equal innerdiameter, and are configured to allow outflow of the fluid fortemperature control, which has passed through an inside of the valvebody portion 35, to the connecting portion 31 of the third flange member27 with little resistance. Meanwhile, a thrust washer 43 is mounted tothe upper shaft support portion 36 to reduce a load generated by thevalve shaft 34 pressed by a sealing case 53 to be described later.

Further, as illustrated in FIG. 3 and FIG. 10 (b), the valve bodyportion 35 has a cylindrical shape having an opening formed therein. Theopening 44 has a substantially half-cylindrical shape with an openingheight H2, which is smaller than an opening height H1 of the first andsecond valve ports 9 and 18. A valve operating portion 45 having theopening 44 of the valve body portion 35 has a half-cylindrical shape(substantially half-cylindrical shape of a cylindrical portion excludingthe opening 44) with a predetermined central angle α (for example,about) 190°. The valve operating portion 45 is arranged in a freelyrotatable manner in the valve seat 8 and held in non-contact with aninner peripheral surface of the valve seat 8 through a slight gap toprevent metal-to-metal biting. Accordingly, with the valve body portion35 positioned above and below the opening 44 included, the valveoperating portion 45 simultaneously switches the first valve port 9 froma closed state to an opened state and the second valve port 18 from anopened state to a closed state in a reverse direction. As illustrated inFIG. 9, upper and lower valve shaft parts 46 and 47 arranged above andbelow the valve operating portion 45 each have a cylindrical shapehaving an outer diameter equal to that of the valve operating portion45, and are held in non-contact with the inner peripheral surface of thevalve seat 8 in a freely rotatable manner through a slight gap. In aninside over the valve operating portion 45, the upper and lower valveshaft parts 46 and 47, and the sealing portion 38, a space 48 isprovided in a state of penetrating the valve shaft 34 toward a loweredge thereof. The space 48 has a columnar shape having a diameterreduced in size toward an upper end thereof.

Further, a cross section of each of both end surfaces 45 a and 45 b ofthe valve operating portion 45 in a circumferential direction (rotationdirection), which is taken along a direction intersecting (orthogonalto) the center axis C, has a curved-surface shape. More specifically, asillustrated in FIG. 11 (a), the cross section of each of the both endportions 45 a and 45 b of the valve operating portion 45 in thecircumferential direction, which is taken along a direction intersectingthe rotation axis C, has an arc shape being convex toward the opening44. A curvature radius of each of the both end portions 45 a and 45 b isset to, for example, a half of a thickness T of the valve operatingportion 45. As a result, a cross section of each of the both endportions 45 a and 45 b is a semicircular shape.

The cross section of each of the both end portions 45 a and 45 b of thevalve operating portion 45 in the circumferential direction, which istaken along a direction intersecting the rotation axis C, is not limitedto an arc shape. It is only necessary that each of the both end surfaces45 a and 45 b in the circumferential direction (rotation direction) havea curved-surface shape. As illustrated in FIG. 11(b), the cross sectionof each of the both end portions 45 a and 45 b of the valve operatingportion 45 in the circumferential direction, which is taken along adirection intersecting the rotation axis C, may have a curved shapeobtained by smoothly connecting a first curved portion 50, which ispositioned on an outer peripheral side, and a second curved portion 51,which is positioned on an inner peripheral side and has a curvatureradius smaller than that of the first curved portion 50.

As illustrated in FIG. 11, when the valve shaft 34 is driven to rotateto open and close the first and second valve ports 9 and 18, in flows ofthe lower temperature fluid and the higher temperature fluid, the bothend portions 45 a and 45 b of the valve operating part 45 in thecircumferential direction are moved (rotated) so as to protrude from orretreat to the ends of the first and second valve ports 9 and 18 in thecircumferential direction. Accordingly, the first and second valve ports9 and 18 are switched from the opened state to the closed state, or fromthe closed state to the opened state. At this moment, each of the bothend portions 45 a and 45 b of the valve operating portion 45 in thecircumferential direction have a cross section having a curved-surfaceshape so as to further linearly change opening areas of the first andsecond valve ports 9 and 18 with respect to a rotation angle of thevalve shaft 34.

Further, as illustrated in FIG. 12, the both end portions 45 a and 45 bof the valve operating portion 45 in the circumferential direction mayeach have a flat shape in a radial direction of the valve operatingportion 45.

As illustrated in FIG. 11 (b), in a case where the cross section of eachof the both end portions 45 a and 45 b of the valve operating portion 45in the circumferential direction has a curved-surface shape, even whenthe opening degree of the valve shaft 34 exceeds 50%, the opening areasof the first and second valve ports 9 and 18 with respect to therotation angle of the valve shaft 34 can be further linearly changed.

As illustrated in FIG. 3, the sealing portion 4 is configured to sealthe valve shaft 34 in a liquid-tight state. The sealing portion 4 hasthe sealing case 53 obtained by forming metal, for example, SUS, into acylindrical shape. The sealing case 53 has an insertion through hole 52through which the valve shaft 34 is inserted. The sealing case 53 isarranged in a recessed portion 54 that is formed in an upper end surfaceof the valve main body 6 and has a columnar shape. The sealing case 53has such structure that a positional relationship between the sealingcase 53 and the valve shaft 34 is determined through annular sealingmembers 55 and 56 and that the sealing case 53 is fixed through apositioning pin (not shown) so as to be prevented from rotating withrespect to a spacer member 59 to be described later. On an innerperipheral surface of the sealing case 53, the two annular sealingmembers 55 and 56 formed of, for example, O-rings for sealing the valveshaft 34 are arranged in a vertical direction. As the sealing members 55and 56, for example, an O-ring made of ethylene-propylene rubber (EPDM)is used. The upper sealing member 56 is retained by a retaining member56 a. Further, the annular sealing member 57 formed of, for example, anO-ring seals the sealing case 53 with respect to the valve main body 6.

The coupling portion 5 is arranged between the valve main body 6, inwhich the sealing portion 4 is provided, and the actuator 3. Thecoupling portion 5 is configured to connect the valve shaft 34 and arotation shaft (not shown), which allows the valve shaft 34 to beintegrally rotated, to each other. The coupling portion 5 includes aspacer member 59, an adaptor plate 60, and a coupling member 62. Thespacer member 59 is arranged between the sealing portion 4 and theactuator 3. The adaptor plate 60 is fixed to an upper portion of thespacer member 59. The coupling member 62 is accommodated in a space 61having a columnar shape formed in a state of penetrating an inside ofthe spacer member 59 and the adaptor plate 60, and connects the valveshaft 34 and the rotation shaft (not shown) to each other. The spacermember 59 is obtained by forming metal, for example, SUS, into aparallelepiped shape, which has substantially the same planar shape asthat of the valve main body 6 and a relatively small height. The spacermember 59 is fixed to both the valve main body 6 and the adaptor plate60 through means such as screw fastening. Further, as illustrated inFIG. 2(c), the adaptor plate 60 is obtained by forming metal, forexample, SUS, into a plate-like shape having a planar polygonal shape.The adaptor plate 60 is mounted to the base 64 of the actuator 3 in afixed state with hexagon socket head cap screws 63.

As illustrated in FIG. 3, the coupling member 62 is obtained by forming,for example, metal, a synthetic resin having heat resistance, orceramics into a columnar shape. A recessed groove 65 is formed so as topenetrate an upper end of the valve shaft 34 in a horizontal direction.The valve shaft 34 is coupled and fixed to the coupling member 62 byfitting a projecting portion 66 of the coupling member 62 into therecessed groove 65. Meanwhile, a recessed groove 67 is formed in anupper end of the coupling member 62 so as to penetrate the couplingmember 62 in a horizontal direction. The rotation shaft (not shown) iscoupled and fixed to the coupling member 62 by fitting a projectingportion (not shown) into the recessed groove 67 of the coupling member62. The spacer member 59 has an opening 68 formed in a side surfacethereof for detecting leakage of a liquid through the insertion throughhole 52 when the liquid leaks from the sealing members 55 and 56. Theopening 68 is set to, for example, Rc 1/16 being a standard for atapered female thread having a bore diameter of about 8 mm.

As illustrated in FIG. 2, the actuator 3 includes the base 64 having aplanar surface having a rectangular shape. A casing 90 is mounted to anupper portion of the base 64 with screws 91. The casing 90 isconstructed as a box body having a rectangular parallelepiped shape,which contains drive means including a stepping motor, an encoder, andthe like. The drive means in the actuator 3 only needs to be capable ofrotating the rotation shaft 58 in a desired direction with predeterminedaccuracy based on control signals, and configuration thereof is notlimited. The drive means includes a stepping motor, a driving forcetransmission mechanism, and an angle sensor. The driving forcetransmission mechanism is configured to transmit a rotational drivingforce of the stepping motor to the rotation shaft 58 throughintermediation of driving force transmission means, for example, a gear.The angle sensor is, for example, an encoder or the like configured todetect a rotation angle of the rotation shaft 58.

In FIG. 2, a reference symbol 92 denotes a stepping motor-side cable,and a reference symbol 93 denotes an angle sensor-side cable. Thestepping motor-side cable 92 and the angle sensor-side cable 93 areconnected to a control device (not shown) configured to control thethree-way motor valve 1.

<Operation of Three-way Motor Valve>

In the three-way motor valve 1 according to the embodiment of thepresent invention, the flow rate of the lower temperature fluid and thehigher temperature fluid is controlled as follows.

As illustrated in FIG. 5, at the time of assembly or adjustment for use,in the three-way motor valve 1, the first flange member 10 and thesecond flange member 19 are removed from the valve main body 6 so thatthe adjusting rings 77 and 87 are exposed to the outside. Under thisstate, when the fastening amounts of the adjusting rings 77 and 87 withrespect to the valve main body 6 are adjusted through use of the jig(not shown), as illustrated in FIG. 7, the protruding amounts of thefirst valve seat 70 and the second valve seat 80 from the valve seat 8of the valve main body 6 are changed. When the fastening amount of theadjusting ring with respect to the valve main body 6 is increased, theconcave portion of the first valve seat 70 or the concave portion of thesecond valve seat 80 protrudes from the inner peripheral surface of thevalve seat 8 of the valve main body 6 so that the gap G1 between theouter peripheral surface of the valve shaft 34 and the concave portionof the first valve seat 70 or the concave portion of the second valveseat 80 is reduced. Meanwhile, when the fastening amount of theadjusting ring with respect to the valve main body 6 is reduced, aprotruding length of the concave portion of the first valve seat 70 orthe concave portion of the second valve seat 80 from the innerperipheral surface of the valve seat 8 of the valve main body 6 isreduced so that the gap G1 between the outer peripheral surface of thevalve shaft 34 and the concave portion of the first valve seat 70 or theconcave portion of the second valve seat 80 is increased.

In the first embodiment of the present invention, the gap G1 between theouter peripheral surface of the valve shaft 34 and the concave portionof the first valve seat 70 or the concave portion of the second valveseat 80 is set to from about 5 μm to about 10 μm. However, the gap G1between the outer peripheral surface of the valve shaft 34 and theconcave portion of the first valve seat 70 or the concave portion of thesecond valve seat 80 is not limited to the above-mentioned value. Thegap G1 may be set to a value smaller than the above-mentioned value, forexample, may satisfy the gap G1=0 μm. Alternatively, the gap G1 may beset to 10 μm or more.

As illustrated in FIG. 1, through the first flange member 10 and thesecond flange member 19, the lower temperature fluid adjusted to apredetermined lower temperature and the higher temperature fluidadjusted to a predetermined higher temperature are supplied throughpipes (not shown) to the three-way motor valve 1. As illustrated in FIG.9(a), for example, in an initial state before start of operation, thethree-way motor valve 1 is brought into a state in which the valveoperating portion 45 of the valve shaft 34 simultaneously closes(completely closes) the first valve port 9 and opens (completely opens)the second valve port 18.

As illustrated in FIG. 3, in the three-way motor valve 1, when thestepping motor (not shown) provided in the actuator 3 is driven torotate by a predetermined amount, the rotation shaft 58 is driven torotate in accordance with a rotation amount of the stepping motor. Inthe three-way motor valve 1, when the rotation shaft 58 is driven torotate, the valve shaft 34 coupled and fixed to the rotation shaft 58 isrotated by an angle equivalent to the rotation amount (rotation angle)of the rotation shaft 58. The valve operating portion 45 is rotated inthe valve seat 8 along with the rotation of the valve shaft 34. Withthis, as illustrated in FIG. 12(a), the one end portion 45 a of thevalve operating portion 45 in the circumferential direction graduallyopens the first valve port 9. As a result, the lower temperature fluidflowing in from the first housing member 10 through the first inflowport 7 flows into the valve seat 8 through the first valve port 9.

At this moment, as illustrated in FIG. 12(a), the another end portion 45b of the valve operating portion 45 in the circumferential directionopens the second valve port 18. Accordingly, the higher temperaturefluid flowing in from the second housing member 19 through the secondinflow port 17 flows into the valve seat 8 through the second valve port18. Then, the higher temperature fluid mixed with the lower temperaturefluid flows out from the third housing member 27 via the valve seat 8through the outflow port 30 of the valve main body 6. A temperature ofthe higher temperature fluid is adjusted to a constant temperature (forexample, 80° C.), which is higher than a temperature of the lowertemperature fluid and is determined in advance.

As illustrated in FIG. 11(b), in the three-way motor valve 1, when thevalve shaft 34 is driven to rotate, and the one end portion 45 a of thevalve operating portion 45 in the circumferential direction graduallyopens the first valve port 9, the lower temperature fluid flowing inthrough the first housing member 10 and the higher temperature fluidflowing in through the second housing member 19 are mixed in the valvechamber 8 and the valve shaft 34, with the result that the fluid fortemperature control is obtained. The fluid for temperature control issupplied to the outside from the third housing member 27 through theoutflow port 30 of the valve main body 6.

In the three-way motor valve 1, the valve shaft 34 is rotated as therotation shaft 58 is driven to rotate. The one end portion 45 a of thevalve operating portion 45 in the circumferential direction graduallyopens the first valve port 9, and at the same time, the another endportion 45 b of the valve operating portion 45 in the circumferentialdirection gradually closes the second valve port 18. The lowertemperature fluid flowing in through the first valve port 9 and thehigher temperature fluid flowing in through the second valve port 18 aremixed in the valve chamber 8 and the valve shaft 34. Then, the resultingfluid for temperature control, which is adjusted in temperature inaccordance with a mixture ratio between the lower temperature fluid andthe higher temperature fluid, is supplied to the outside through theoutflow port 30 of the valve main body 6.

Further, in the three-way motor valve 1, each of the both end portions45 a and 45 b of the valve operating portion 45 in the circumferentialdirection has a cross section having a curved-surface shape or a planarshape. Thus, the opening areas of the first and second valve ports 9 and18 can be linearly changed with respect to the rotation angle of thevalve shaft 34. Further, it is conceivable that the lower temperaturefluid and the higher temperature fluid regulated in flow rate by theboth end portions 45 a and 45 b of the valve operating portion 45 flowin a form of a nearly laminar flow. Therefore, the mixture ratio (flowrate) between the lower temperature fluid and the higher temperaturefluid can be controlled with high accuracy in accordance with theopening areas of the first valve port 9 and the second valve port 18.

In the three-way motor valve 1 according to the first embodiment of thepresent invention, as described above, under an initial state, the valveoperating portion 45 of the valve shaft 34 simultaneously closes(completely closes) the first valve port 9 and opens (completely opens)the second valve port 18.

At this time, in the three-way motor valve 1, when the valve operatingportion 45 of the valve shaft 34 closes (completely closes) the firstvalve port 9, ideally, the flow rate of the lower temperature fluidbeing the first fluid should be zero.

However, as illustrated in FIG. 7, in the three-way motor valve 1, inorder to prevent metal-to-metal biting of the valve shaft 34 into theinner peripheral surface of the valve seat 8, the valve shaft 34 isprovided in a freely rotatable manner so as to be held in non-contactwith the valve seat 8 with a slight gap between the outer peripheralsurface of the valve shaft 34 and the inner peripheral surface of thevalve seat 8. As a result, the slight gap G2 is defined between theouter peripheral surface of the valve shaft 34 and the inner peripheralsurface of the valve seat 8. Accordingly, in the three-way motor valve1, even when the valve operating portion 45 of the valve shaft 34 closes(completely closes) the first valve port 9, the flow rate of the lowertemperature fluid does not become zero, and a small amount of the lowertemperature fluid flows to the second valve port 18 side through theslight gap G2 defined between the outer peripheral surface of the valveshaft 34 and the inner peripheral surface of the valve seat 8.

Incidentally, in the three-way motor valve 1 according to the firstembodiment of the present invention, as illustrated in FIG. 7, the firstvalve seat 70 and the second valve seat 80 include the concave portion74 and the concave portion 84, respectively. The concave portion 74 orthe concave portion 84 protrudes from the inner peripheral surface ofthe valve seat 8 toward the valve shaft 34 side, thereby partiallyreducing the gap G1 between the outer peripheral surface of the valveshaft 34 and the inner peripheral surface of the valve seat 8.

Therefore, in the three-way motor valve 1, in order to preventmetal-to-metal biting of the valve shaft 34 into the inner peripheralsurface of the valve seat 8, even when the valve shaft 34 is provided ina freely rotatable manner so as to be held in non-contact with the valveseat 8 with the slight gap between the outer peripheral surface of thevalve shaft 34 and the inner peripheral surface of the valve seat 8,inflow of the lower temperature fluid through the first valve port 9into the slight gap G2 defined between the outer peripheral surface ofthe valve shaft 34 and the inner peripheral surface of the valve seat 8is significantly restricted and suppressed by the gap G1 that is aregion corresponding to a partially reduced gap between the outerperipheral surface of the valve shaft 34 and the inner peripheralsurface of the valve seat 8.

Accordingly, the three-way motor valve 1 can significantly suppressleakage of the fluid when the three-way motor valve completely closesthe valve port as compared to a three-way motor valve that does notinclude the concave portions 74 and 84 formed to partially reduce thegap between the valve shaft 34 and the first valve seat 70, which isopposed to the valve shaft 34, and the gap between the valve shaft 34and the second valve seat 80, which is opposed to the valve shaft 34.

Further, similarly, the three-way motor valve 1 can significantlysuppress leakage and inflow of the higher temperature fluid, which isthe second fluid, through the second valve port 18 to the lowertemperature fluid side even when the valve operating portion 45 of thevalve shaft 34 closes (completely closes) the second valve port 18.

Experiment Example 1

The inventors of the present invention experimentally produced thethree-way motor valves 1 respectively including the valve shafts 34 asillustrated in FIG. 10(a) and FIG. 10(b), and carried out an experimentto check how a flow coefficient Cv value of each of the lowertemperature fluid and the higher temperature fluid changes in accordancewith opening degrees of the first valve port 9 and the second valve port18 along with the rotation of the valve shaft 34.

The flow coefficient Cv value of each of the lower temperature fluid,the higher temperature fluid, and the fluid for temperature control,which is a mixture of the lower temperature fluid and the highertemperature fluid, were measured by moving one flow rate sensor havinghigh detection accuracy to each of the first valve port 9, the secondvalve port 18, and the outflow port 30 individually at the timing whenthe rotation angle of the valve shaft 34 was changed.

FIG. 13 and FIG. 14 are graphs for showing results of theabove-mentioned examples. FIG. 13 corresponds to the valve shaft of FIG.11(a), and FIG. 14 corresponds to the valve shaft of FIG. 11(b).

As a result, as is apparent from the graphs shown in FIG. 13 and FIG.14, the flow coefficient Cv value of the lower temperature fluid wassubstantially linearly increased along with the rotation angle of thevalve shaft 34. Simultaneously, the flow coefficient Cv value of thehigher temperature fluid was substantially linearly reduced. It has beenrevealed that the mixture ratio (flow rate) between the lowertemperature fluid and the higher temperature fluid can be controlledwith high accuracy. Further, as is apparent from the graphs shown inFIG. 13 and FIG. 14, in a region where the opening degree of the valveshaft 34 was 50% or more, the valve shafts of FIG. 11 (a) and FIG. 11(b)each had a region where the flow coefficient Cv value was slightlydeviated from the linear line. The reason for this is assumed to bederived from the curved-surface shape of each of the both end portions45 a and 45 b because, in the case of the valve shaft of FIG. 11 (b),the region where the flow coefficient Cv value was slightly deviatedfrom the linear line was shifted to the region where the opening degreeof the valve shaft 34 was higher as compared to the case of the valveshaft of FIG. 11(a).

In the graph shown in FIG. 14, it can be seen that the flow coefficientCv value of one fluid did not become completely zero even when the valveshaft 34 was rotated to a completely closed position. This is probablybecause the curvature radius of the outer peripheral side of each of theboth end portions 45 a and 45 b of the valve operating portion 45 in thecircumferential direction was set larger.

Experiment Example 2

Further, the inventors of the present invention experimentally producedthe three-way motor valve 1 including the first valve seat 70 and thesecond valve seat 80 as illustrated in FIG. 3 and FIG. 4, and carriedout an experiment to measure how much the flow rate (leakage amount) ofthe lower temperature fluid was when the first valve port 9 wascompletely closed along with rotation of the valve shaft 34. Theexperiment was carried out under conditions in which the slight gap G1defined between the outer peripheral surface of the valve shaft 34 andthe inner peripheral surface of the valve seat 8 was varied among 150μm, 28 μm, and 6.5 μm, and a difference in pressure of the lowertemperature fluid between an upstream side and a downstream side of thefirst valve port 9 was varied between 0.44 MPa and 0.68 MPa.

FIG. 15 is a table for showing results of Experiment Example 2.

As is apparent from FIG. 15, in a case in which the gap (clearance)between the outer peripheral surface of the valve shaft and the innerperipheral surface of the valve seat of the valve main body is 150 μm,when the difference in pressure between the first inflow port and theoutflow port is 0.44 MPa, a leakage amount per minute is 2.20 L/min.When the difference in pressure between the first inflow port and theoutflow port is 0.68 MPa, the leakage amount per minute is significantlyincreased to 2.73 L/min.

In contrast, in Experiment Example 2, in a case in which the gap(clearance) between the outer peripheral surface of the valve shaft andthe inner peripheral surface of the valve seat of the valve main body isset to 28 μm, when the difference in pressure between the first inflowport and the outflow port is 0.44 MPa, the leakage amount per minute is0.21 L/min. Even when the difference in pressure between the firstinflow port and the outflow port is 0.68 MPa, it can be seen that theleakage amount per minute is significantly reduced to 0.26 L/min.

Moreover, in Experiment Example 2, in a case in which the gap (radialclearance) between the outer peripheral surface of the valve shaft andthe inner peripheral surface of the valve seat of the valve main body isset to 6.5 μm, when the difference in pressure between the first inflowport and the outflow port is 0.44 MPa, the leakage amount per minute is0.08 L/min. Even when the difference in pressure between the firstinflow port and the outflow port is 0.68 MPa, it can be seen that theleakage amount per minute is further significantly reduced to 0.10L/min.

Second Embodiment

FIG. 16 is a view for illustrating a three-way motor valve as oneexample of a flow rate control valve according to a second embodiment ofthe present invention.

The three-way motor valve 1 according to the second embodiment isstructured as the three-way motor valve 1 configured to divide the samefluid into two parts instead of mixing two kinds of different fluids.

The three-way motor valve 1 for division has the same structure as thatof the above-mentioned three-way motor valve 1 for mixture. However, asillustrated in FIG. 16, the three-way motor valve 1 for division has aninflow port 26 in a lower end portion of the valve main body 6, and hasa first outflow port 7 and a second outflow port 17 in both sidesurfaces of the valve main body 6, respectively. The other componentsare the same as those of the above-mentioned three-way motor valve 1 formixture.

Third Embodiment

FIG. 17 is a view for illustrating a two-way motor valve as one exampleof a flow rate control valve according to a third embodiment of thepresent invention.

The two-way motor valve 1 according to the third embodiment isstructured as a two-way motor valve 1 for flow rate control, which isconfigured to control a flow rate of one kind of a fluid.

That is, as illustrated in FIG. 17, the two-way motor valve 1 for flowrate control has the single inflow port 17 in one side surface of thevalve main body 6, and has the outflow port 26 in a bottom surface ofthe valve main body 6. The other components are the same as those of theabove-mentioned three-way motor valve 1 for mixture.

Example 1

FIG. 18 is a schematic diagram for illustrating a constant-temperaturemaintaining device (chiller device) to which the three-way motor valvefor flow rate control according to the first embodiment of the presentinvention is applied.

A chiller device 100 is, for example, used for a semiconductormanufacturing apparatus involving plasma etching, and configured tomaintain a temperature of a semiconductor wafer or the like as oneexample of a temperature control target W to a constant temperature. Thetemperature control target W, for example, a semiconductor wafer, mayrise in temperature along with generation or discharge of plasma or thelike after being subjected to plasma etching or the like.

The chiller device 100 includes a temperature control portion 101constructed to have a table-like shape as one example of the temperaturecontrol means arranged so as to be held in contact with the temperaturecontrol target W. The temperature control portion 101 has a flow passage102 for temperature control therein. The fluid for temperature control,which includes the lower temperature fluid and the higher temperaturefluid having been adjusted in mixture ratio, flows through the flowpassage 102 for temperature control.

The three-way motor valve 1 is connected to the flow passage 102 fortemperature control in the temperature control portion 101 through anopen/close valve 103. A constant-temperature reservoir 104 for lowertemperature is connected to the first flange portion 10 of the three-waymotor valve 1. The constant-temperature reservoir 104 for lowertemperature stores the low temperature fluid adjusted to a predeterminedlower temperature. The lower temperature fluid is supplied to thethree-way motor valve 1 from the constant-temperature reservoir 104 forlower temperature by a first pump 105. Further, a constant-temperaturereservoir 106 for higher temperature is connected to the second flangeportion 19 of the three-way motor valve 1. The constant-temperaturereservoir 106 for higher temperature stores the high temperature fluidadjusted to a predetermined higher temperature. The higher temperaturefluid is supplied to the three-way motor valve 1 from theconstant-temperature reservoir 106 for higher temperature by a secondpump 107. The third flange member 27 of the three-way motor valve 1 isconnected to the flow passage 102 for temperature control in thetemperature control portion 101 through the open/close valve 103.

Further, on an outflow side of the flow passage 102 for temperaturecontrol in the temperature control portion 101, a pipe for returning isprovided. The pipe for returning is connected to theconstant-temperature reservoir 104 for lower temperature and theconstant-temperature reservoir 106 for higher temperature.

The three-way motor valve 1 includes a stepping motor 108 configured todrive the valve shaft 34 to rotate. Further, a temperature sensor 109configured to detect a temperature of the temperature control portion101 is provided to the temperature control portion 101. The temperaturesensor 109 is connected to a control device (not shown), and the controldevice is configured to control a drive of the stepping motor 108 of thethree-way motor valve 1.

As illustrated in FIG. 18, in the chiller device 100, a temperature ofthe temperature control target W is detected by the temperature sensor109. Based on a detection result obtained by the temperature sensor 109,the rotation of the stepping motor 108 of the three-way motor valve 1 iscontrolled by the control device. Accordingly, the temperature controltarget W is controlled to a temperature equal to a predeterminedtemperature.

When the valve shaft 34 is driven to rotate by the stepping motor 108,the three-way motor valve 1 controls the mixture ratio between the lowertemperature fluid, which is supplied from the constant-temperaturereservoir 104 for lower temperature by the first pump 105, and thehigher temperature fluid, which is supplied from theconstant-temperature reservoir 106 for higher temperature by the secondpump 107, to control a temperature of the fluid for temperature control,which is a mixture of the lower temperature fluid and the highertemperature fluid to be supplied to the flow passage 102 for temperaturecontrol in the temperature control portion 101 from the three-way motorvalve 1 through the open/close valve 103.

At this moment, as illustrated in FIG. 13, the three-way motor valve 1is capable of controlling the mixture ratio between the lowertemperature fluid and the higher temperature fluid in accordance withthe rotation angle of the valve shaft 34 with high accuracy, therebybeing capable of finely adjusting a temperature of the fluid fortemperature control. Thus, the chiller device 100 using the three-waymotor valve 1 according to the embodiment of the present invention iscapable of controlling a temperature of the temperature control targetW, which is held in contact with the temperature control portion 101, toa desired temperature, by allowing the fluid for temperature control,which is controlled in mixture ratio between the lower temperature fluidand the higher temperature fluid and adjusted in temperature to apredetermined temperature, to flow through the flow passage 102 fortemperature control in the temperature control portion 101.

Example 2

FIG. 19 is a schematic diagram for illustrating a constant-temperaturemaintaining device (chiller device) to which the three-way valve forflow rate control according to the second embodiment of the presentinvention is applied.

The chiller device 100 uses the three-way motor valve 1 in order todivide a fluid for control, which has flowed through the flow passage102 for temperature control of the temperature control portion 101,between the constant-temperature reservoir 104 for lower temperature andthe constant-temperature reservoir 106 for higher temperature. When thevalve shaft 34 is driven to rotate by a stepping motor 110, thethree-way motor valve 1 controls a flow rate of the fluid for control tobe divided between the constant-temperature reservoir 104 for lowertemperature and the constant-temperature reservoir 106 for highertemperature.

In a mixing portion 111 in which the lower temperature fluid suppliedfrom the constant-temperature reservoir 104 for lower temperature by thefirst pump 105, and the higher temperature fluid supplied from theconstant-temperature reservoir 106 for higher temperature by the secondpump 107 are mixed together, there is used mixing means for mixing thelower temperature fluid and the higher temperature fluid as appropriateafter controlling the flow rate of the lower temperature fluid and theflow rate of the higher temperature fluid. As a matter of course, asdescribed above, the three-way motor valve 1 for mixing may be used asthe mixing means.

INDUSTRIAL APPLICABILITY

The flow rate control valve is capable of suppressing leakage of a fluidwhen the flow rate control valve completely closes a valve port. Throughuse of the flow rate control valve in the temperature control device, atemperature of the temperature control target can be controlled withhigh accuracy.

REFERENCE SIGNS LIST

-   -   1 . . . three-way motor valve    -   2 . . . valve portion    -   3 . . . actuator    -   4 . . . sealing portion    -   5 . . . coupling portion    -   6 . . . valve main body    -   7 . . . first inflow port    -   8 . . . valve seat    -   9 . . . first valve port    -   10 . . . first flange member    -   11 . . . hexagon socket head cap screw    -   12 . . . flange portion    -   13 . . . insertion portion    -   14 . . . pipe connecting portion    -   15 . . . O-ring    -   16 . . . chamfer    -   17 . . . second inflow port    -   18 . . . second valve port    -   19 . . . second flange member    -   20 . . . hexagon socket head cap screw    -   21 . . . flange portion    -   22 . . . insertion portion    -   23 . . . pipe connecting portion    -   34 . . . valve shaft    -   35 . . . valve body portion    -   45 . . . valve operating portion    -   45 a, 45 b . . . both end portion    -   70, 80 . . . first and second valve seat    -   74, 84 . . . concave portion (gap reducing portion)

The invention claimed is:
 1. A flow rate control valve, comprising: avalve main body including a valve seat, the valve seat having a columnarspace and having a plurality of valve ports, which allow a fluid to flowtherethrough and each have a rectangular cross section; a valve bodybeing provided in a freely rotatable manner in the valve seat of thevalve main body so as to open and close the plurality of valve ports,the valve body having a cylindrical shape and having an opening formedin an outer peripheral surface of the valve body; a gap reducing portionbeing provided so as to partially reduce a gap between the valve bodyand a member opposed to the valve body; and drive means for driving thevalve body to rotate, wherein the plurality of valve ports are eachformed by a valve port forming member, which is a member providedseparately from the valve main body, and wherein the gap reducingportion is formed of a distal end portion of the valve port formingmember opposed to the valve body.
 2. A flow rate control valve,comprising: a valve main body including a valve seat, the valve seathaving a columnar space and having a first valve port, which allowsinflow of a first fluid and has a rectangular cross section, and asecond valve port, which allows inflow of a second fluid and has arectangular cross section; a valve body being provided in a freelyrotatable manner in the valve seat of the valve main body so as tosimultaneously switch the first valve port from a closed state to anopened state and switch the second valve port from an opened state to aclosed state, the valve body having a half-cylindrical shape with apredetermined central angle and having a curved-surface shape or aflat-surface shape at each of both end surfaces of the valve body in acircumferential direction; a gap reducing portion being provided so asto partially reduce a gap between the valve body and a member opposed tothe valve body; and drive means for driving the valve body to rotate,wherein the plurality of valve ports are each formed by a valve portforming member, which is a member provided separately from the valvemain body, and wherein the gap reducing portion is formed of a distalend portion of the valve port forming member opposed to the valve body.3. A flow rate control valve, comprising: a valve main body including avalve seat, the valve seat having a columnar space and having a firstvalve port, which allows outflow of a fluid and has a rectangular crosssection, and a second valve port, which allows outflow of the fluid andhas a rectangular cross section; a valve body being provided in a freelyrotatable manner in the valve seat of the valve main body so as tosimultaneously switch the first valve port from a closed state to anopened state and switch the second valve port from an opened state to aclosed state, the valve body having a half-cylindrical shape with apredetermined central angle and having a curved-surface shape or aflat-surface shape at each of both end surfaces of the valve body in acircumferential direction; a gap reducing portion being provided so asto partially reduce a gap between the valve body and a member opposed tothe valve body; and drive means for driving the valve body to rotate,wherein the plurality of valve ports are each formed by a valve portforming member, which is a member provided separately from the valvemain body, and wherein the gap reducing portion is formed of a distalend portion of the valve port forming member opposed to the valve body.4. A flow rate control valve, comprising: a valve main body including avalve seat having a columnar space, the valve main body having a firstvalve port, which allows a fluid to flow therethrough and has arectangular cross section, and a second valve port, which allows thefluid to flow therethrough, the first valve port being formed in aperipheral surface of the valve seat, the second valve port being formedin one end portion of the valve seat in an axial direction; a valve bodybeing provided in a freely rotatable manner in the valve seat of thevalve main body, the valve body having a shape corresponding to part ofa cylindrical shape with a predetermined central angle, so as tolinearly change an opening area of the first valve port; a gap reducingportion being provided so as to partially reduce a gap between the valvebody and a member opposed to the valve body; and drive means for drivingthe valve body to rotate, wherein the plurality of valve ports are eachformed by a valve port forming member, which is a member providedseparately from the valve main body, and wherein the gap reducingportion is formed of a distal end portion of the valve port formingmember opposed to the valve body.
 5. The flow rate control valveaccording to any one of claims 1 to 4, further comprising a gapadjusting member configured to adjust a gap between the valve body andthe gap reducing portion.
 6. A temperature control device, comprising:temperature control means having a flow passage for temperature control,which allows a fluid for temperature control to flow therethrough, thefluid for temperature control including a lower temperature fluid and ahigher temperature fluid adjusted in mixture ratio; a first pipe forsupplying the lower temperature fluid adjusted to a first predeterminedlower temperature; a second pipe for supplying the higher temperaturefluid adjusted to a second predetermined higher temperature; and a flowrate control valve connected to the first pipe and the second pipe, andconfigured to adjust the mixture ratio between the lower temperaturefluid supplied from the first pipe and the higher temperature fluidsupplied from the second pipe and allow the fluid for temperaturecontrol to flow through the flow passage for temperature control,wherein the flow rate control valve of claim 1 or 2 is used as the flowrate control valve.
 7. A temperature control device, comprising:temperature control means having a flow passage for temperature control,which allows a fluid for temperature control to flow therethrough, thefluid for temperature control including a lower temperature fluid and ahigher temperature fluid adjusted in mixture ratio; a first pipe forsupplying the lower temperature fluid adjusted to a first predeterminedlower temperature; a second pipe for supplying the higher temperaturefluid adjusted to a second predetermined higher temperature; a mixingportion, which is connected to the first pipe and the second pipe, formixing the lower temperature fluid supplied from the first pipe and thehigher temperature fluid supplied from the second pipe and supplying amixture of the lower temperature fluid and the higher temperature fluidto the flow passage for temperature control; and a flow rate controlvalve configured to divide the fluid for temperature control havingflowed through the flow passage for temperature control between thefirst pipe and the second pipe while controlling a flow rate of thefluid for temperature control, wherein the flow rate control valve ofclaim 1 or 3 is used as the flow rate control valve.